I am testing Blackberry Enterprise Server with a Simulator 8100T. While testing using the simulator, initially I had issues connecting the dekstop manager and the simulator.
That is now recotified. Now the issue I am facing is, whenver I try to activate a user thru the simulator, I get an error - Network connectivity unavialable. Activiation failed.

Steps i followed:
1. Install the above 3 setups in the same order as shown above.
2. Start the Desktop Manager and minimize it.
3. Start the simulator.
4. In the BlackBerry Simulator, click Turn Wireless Off.
5. Open BlackBerry Desktop Manager 4.0 or later , BlackBerry Device Manager 4.0 automatically gets opened up.
6. From the BlackBerry Simulator, click Simulate and select USB Connected or Serial Connected.
7. It will show a prompt that “No devices to Synchronize”
8. Once connected the blackberry simulator will show text that it is connected to desktop.
9. Now trun off the BlackBerry simulator by pressing down the red button for a while and close the application by File- Exit
10. Remove the net_rim_sdk_simulationSB.cod file from the BlackBerry Simulator directory - C:\Program Files\Research In Motion\BlackBerry Device Simulators 4.2.0\4.2.0.42 (8100-T-MobileUS)
11. After doing so, delete all the .DMP files from the same directory
12. Start the BlackBerry Simulator, and repeat the steps 4 to 6.
13. Once connected to the desktop start Enterprise Activation, On the screen it will show the PIN of the device, note it down and close the Enterprise Activation and return to home screen.
14. Start the BES manager, select Find Handheld -> Enter the noted PIN of the installed simulator.

15. and during enterprise activation when i entered BES username and password I got error as "Network connectivity unavialable. Activiation failed.
"